4x12 Series-Parallel / Parallel-Series Wiring

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Post by Scumback Speakers » Sat Mar 01, 2008 9:16 pm

bruce wrote:I've noticed the newer Marshall cabs that are half open-back and house the silver alnicos are wired in parallel-series. Maybe this conserves the amount of wire used compared to the old 60 and 70's way.
Saw that, too. It sure saves them about 3 feet of wire per cab.
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Post by bruce » Sun Mar 02, 2008 1:50 am

Jim,

Can you tell me the wire you use to wire up cabs and where I can find it. I saw it posted here a while back, but can't find it now. I'm just north of Los Angeles BTW. I want to re-wire a couple cabs in the parallel-series... it looks so damn tidy!

Thanks!

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Post by Scumback Speakers » Sun Mar 02, 2008 3:49 am

16 gauge lamp aka as zip cord. Home Depot, comes in red & black about 10 foot lengths.
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Post by rgorke » Wed Mar 05, 2008 1:59 pm

Southbay Ampworks wrote:16 gauge lamp aka as zip cord. Home Depot, comes in red & black about 10 foot lengths.
Do you use solder the connections or use female clip on connectors?

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Re: 4x12 Series-Parallel / Parallel-Series Wiring

Post by hunter » Fri Feb 05, 2010 8:10 am

I just bought a Vintage Marshall cab which was rewired to 4 Ohms, so when I was thinking about the best way to wire back to 16, I was confronted with this topic.

Now there was a hole drilled in the back which was closed with a metal panel, so I used this to implement a switch, to be able to A/B both options. And I have to say, there is a difference, not even subtle when you're in the room.

I also did two sound files, using a Tascam DR-1 to try and capture the room. I think even on this recording you can hear a difference - both recordings made 2 minutes apart, all settings identical, just switched amp to standby to switch the cab.

Here are the two files, which are named in "vintage" and "modern". Vintage relates to below schematic with the white wire disconnected. Modern relates to the setting where the white wire is connected.

Vintage (disconnected):
http://www.klangforschungszentrum.de/te ... intage.mp3

Modern (connected):
http://www.klangforschungszentrum.de/te ... modern.mp3

I used a schematic from Acys-Lounge.de which I attach here.
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AGL_4x12_schalt_16ohm.jpg
AGL_4x12_schalt_16ohm.jpg (138.39 KiB) Viewed 6327 times

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Re: 4x12 Series-Parallel / Parallel-Series Wiring

Post by Scumback Speakers » Fri Feb 05, 2010 9:03 am

Since working with Dave Friedman we've been going down a bunch of avenues in cab wiring, and wire used for tone tests.

During NAMM I rewired one of my M75 65w loaded 69 spec straight cabs with this wiring, which I'll call "Parallel-Series 4x12 Alternate" wiring. As Shakti has stated before, correctly, if you think of going from the speaker to the jack, the naming scheme makes sense.

Image

With identical M75 65w loaded cabs, this wiring diagram yields a bit more lows and low mids versus the standard series/parallel wiring more commonly found in the older 60's cabs I've had. In fact I've never bought one original Marshall cab (out of 60 or more) that had this wiring, but it seems they were produced.

In any event with M magnet speakers, this "Parallel-Series 4x12 Alternate" wiring produced a bit more lows & low mids in a closed back 4x12 straight cab versus the series/parallel wiring pictured below.

Image

I have not tried the Parallel-Series wiring with H75/H55 or Scumnicos yet, but as soon as I have enough speakers to compare those in stock I will and report back on how that sounds.
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Re: 4x12 Series-Parallel / Parallel-Series Wiring

Post by hunter » Fri Feb 05, 2010 9:17 am

Southbay Ampworks wrote:Since working with Dave Friedman we've been going down a bunch of avenues in cab wiring, and wire used for tone tests.

During NAMM I rewired one of my M75 65w loaded 69 spec straight cabs with this wiring, which I'll call "Parallel-Series 4x12 Alternate" wiring. As Shakti has stated before, correctly, if you think of going from the speaker to the jack, the naming scheme makes sense.

Image

With identical M75 65w loaded cabs, this wiring diagram yields a bit more lows and low mids versus the standard series/parallel wiring more commonly found in the older 60's cabs I've had. In fact I've never bought one original Marshall cab (out of 60 or more) that had this wiring, but it seems they were produced.

In any event with M magnet speakers, this "Parallel-Series 4x12 Alternate" wiring produced a bit more lows & low mids in a closed back 4x12 straight cab versus the series/parallel wiring pictured below.

Image

I have not tried the Parallel-Series wiring with H75/H55 or Scumnicos yet, but as soon as I have enough speakers to compare those in stock I will and report back on how that sounds.
So even within Parallel/Series, there are differences? Well this is not getting any easier :lol:

Your upper schematic is identical to the one I used with the white wire disconnected. I haven't tried the other one you posted, but to be honest, I have enough from turning screws and burning fingers for today :|

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Re: 4x12 Series-Parallel / Parallel-Series Wiring

Post by 908ssp » Sat Feb 06, 2010 9:34 am

Electrically those should be the same. In the top picture the plus wire goes to the left speaker then the right speaker then to the negative terminal. In the bottom picture the plus wire goes to the top left speaker then to the lower left speaker then to the negative terminal. Exactly the same as the other diagram except one speaker is on top of the other instead of next to the other. The fact that the plus wire splits in two at the jack or at one of the speaker terminals should make absolutely no difference. Both of those diagrams are series / parallel.

The top drawing works great with modern speakers two big push on tabs on each speaker. The lower works better with vintage speakers as all they have was little tiny hooks and only one, so getting two wires hooked to the little hooks and soldered is a PITA.

Both of the drawings above match the top drawing in the picture below. The lower picture is the parallel/series option.


Image

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Re: 4x12 Series-Parallel / Parallel-Series Wiring

Post by BowerR64 » Sat Feb 13, 2016 12:14 am

old post i know but wanted to add something.

If you look at older 3 way speakers, or even 2 way speakers some use a "crossover" that changes or filters the sound going to each driver. Sometimes they add a "choke" that usually runs to the woofer. This cuts some of the highs out so the woofer sees more low end then say the midrange.

When you run a driver in series you sort of do the same thing, your running threw one coil sort of like the choke in a cross over network so the second speaker gets a slightly "choked" signal IMO this does something tot he lower frequencies that i like better.

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